Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of oil and gas producer Carrizo Oil & Gas (Nasdaq: CRZO) were spouting higher today, gaining as much as 10% in intraday trading as investors flocked to shale plays in the energy sector.

So what: Like many other independent energy companies, Carrizo has been shifting more of its focus recently to oil in favor of gas as natural gas prices continue to slump while oil prices soar. Today energy giant Apache (NYSE: APA) announced that it is acquiring privately held Cordillera Energy Partners specifically for Cordillera's shale-oil reserves. Apache is paying $2.9 billion for Cordillera.

Now what: What's key for investors to keep in mind today is that the Apache deal doesn't change the underlying fundamentals at Carrizo. So why the big pop in the stock? For those investors that think that Carrizo is currently undervalued, industry deal-making could be an encouraging sign that the market will start to value Carrizo at its full value. At the same time, some investors may simply be speculating on the possibility that shale-oil excitement will bring a rich acquirer to Carrizo's doorstep.

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Fool contributor Matt Koppenheffer does not have a financial interest in any of the companies mentioned. You can check out what Matt is keeping an eye on by visiting his CAPS portfolio, or you can follow Matt on Twitter @KoppTheFool or Facebook. The Fool's disclosure policy prefers dividends over a sharp stick in the eye.